Cutter bit and support therefor having resilient detent means



Dec. '31, 1963 cQF. QSGQOD 3,116,052

CUTTER BIT AND SUPPORT THEREFOR HAVING RESILIENT DETENT MEANS Filed Dec.1, 1959 2 She ets-Sheet 1 zw'w 2 I0 2| EF m/ 22 2 INYENTORZ Dec. 31,1963 c, QSGQOD 3,116,052

. CUTTER BIT AND SUPPORT THEREFOR HAVING RESILIENT DETENT MEANS 2Sheets-Sheet 2 FIG-J5. 3

| l I %-44 42 45 INVENTOR.

United States Patent 3,116,052 CUTTER BIT AND SUPIURT THEREFOR HAVINGRESILIENT DETENT MEANS Charles F. Osgood, Franklin, Pa., assignor to JoyManuiaeturing Company, Pittsburgh, Pa, a corporation of PennsylvaniaFiled Dec. 1, 195%, Ser. No. 856,588 2 Claims. (Cl. 262-33) Thisinvention relates to a cutter bit and support therefor and moreparticularly to improved resilient detent means on the support andengaging the bit for not only holding the bit in cutting position butalso for imparting an inward thrust to the bit shank.

It is becoming common practice to hold a mining machine cutter bit incutting position on its support by yieldable detent means which may bereleased simply by applying an outward prying action to the bit. Thepresent invention contemplates improvements over known forms ofyieldable detent means in that the detent element not only serves tohold the cutter bit in position on its support but also imparts aninward thrust to the bit shank. In a preferred embodiment torsionalforces are built up in a suitable manner within the yieldable mountingfor the detent element, as for example, by insertion of the bit shankinto the support socket, and such torsional forces act on the detentelement to cause the latter to impart an inward thrust to the bit shank.

An object of the present invention is to provide an improved yieldabledetent means for engagement with a bit shank for holding a cutter bit incutting position on its support. Another object is to provide animproved yieldable detent means which not only holds the cutter bit incutting position on its support but also serves to impart an inwardthrust to the bit shank to hold a shoulder on the outer cutting portionof the bit against an outer surface of the bit support. A further objectis to provide an improved yieldable mounting for a detent element notonly for holding the latter in engagement with a notch on the bit shankbut also for imparting through the detent element an inward thrust tothe bit shank.

Still another object is to provide an improved yieldable detent meanscomprising a yieldable mounting in the form of a molded resilient plugof elastomeric material such as rubber bonded in shear to the innerwalls of a metal sleeve and a detent element having a body portionembedded in the elastomeric material of the plug and projectingoutwardly through an open side of the sleeve into engagement with theshank of a cutter bit. A still further object is to provide an improvedyieldable detent means which may be pressed under load, as for example,upon insertion of a bit shank in a support socket, and as a result ofsuch preloading imparting a yieldable inward thrust to the bit shank tohold the cutter bit firmly in cutting position on its support. These andother objects and advantages of the invention will, however, hereinaftermore fully appear in the course of the ensuing description.

In the accompanying drawings there are shown for purposes ofillustration several forms and modifications which the invention mayassume in practice.

In these drawings:

FIG. 1 is a longitudinal vertical section through a preferred form ofbit support and yieldable detent means, and showing a cutter bit held insupported position by the detent means.

FIG. 2 is a detail section taken on line 2-2 of FIG. 1.

FIG. 3 is a fragmentary view taken on the plane of FIG. 1 showing thebit shank in partly inserted position in the support socket, with thedetent means released.

FIG. 4 is a perspective view of the detent element.

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FIG. 5 is a perspective view of the cutter bit.

FIG. 6 is a longitudinal vertical section similar to FIG. 1, showing amodification.

FIGS. 7 and 8 are detail views showing another modified detent means.

FIG. 9 is a detail section taken on line 9-9 of FIG. 6.

FIG. 10 is a longitudinal vertical section similar to FIG. 6, with thebit shank partially inserted in the support socket, and with the detentmeans released.

FIG. 11 is a fragmentary perspective view of the cutter bit shown inFIGS. 6 and 10.

FIG. 12 is a perspective view of the modified detent element of FIGS. 6and 9.

FIG. 13 is a longitudinal vertical sectional view of a bit support anddetent means constructed in accordance with a further modification.

FIG. 14 is a detail section taken on line 14.14 of FIG. 13.

FIG. 15 is a view similar to FIG. 13 showing the bit shank in partiallyinserted position, with the detent means released.

FIG. 16 is a perspective view of the modified detent element of FIGS.13, 14 and 15.

FIG. 17 is a fragmentary perspective view of the shank of the cutter bitof FIG. 13.

FIG. 18 is a longitudinal vertical section taken through still anothermodified construction.

FIG. 19 is a detail section taken on line 19'19 of FIG. 18.

FIG. 20 is a view similar to FIG. 19' showing the detent element held inreleased position by a releasing instrument, with the latter indicatedin dotted lines.

FIG. 21 is a perspective view of the modified detent element of FIGS. 18and l9.

FIG. 22 is a fragmentary perspective view of the shank of the cutter bitof FIG. 18.

FIG. 23 is a longitudinal vertical section of a cutter bit and detentmeans constructed in accordance with still another modified form of theinvention.

FIG. 24 is a detail section taken on line 24--24 of FIG. 23, with adetent rotating tool indicated in dotted lines.

FIG. 25 is a view similar to FIG. 23 with the bit shank in partiallyinserted position and the detent means in released position.

FIG. 26 is a detail section taken on line 2626 of FIG. 25.

FIG. 27 is a perspective view of the modified detent element shown inFIG. 23.

In the form of the invention'shown in FIGS. 1 to 5 inclusive a bitsupport 1 has a conventional socket 2 of rectangular cross section forreceiving the rectangular shank 3 of a cutter bit 4. The bit has anouter head portion 5 carrying a hard metal cutting point 6 and formedwith an inwardly facing rearward shoulder 7 adapted to rest at 8 againstan outer surface of the bit support. The bit head has a forward shoulder9 adapted for engagement by a suitable bit releasing instrument forprying the bit shank from the support socket, in a known manner. inginto the support-socket and in which is fitted a metal sleeve 11 ofcylindric form within which a resilient mount- I ing in the form of aresilient plug or block 12 of elastomeric material such as rubber isbonded in torsional shear to the inner sleeve-wall. A detent element 13has a cylindric body portion 14 embedded within the resilient block andto which the elastomeric material is bonded and projecting from the bodyportion is a curved detent portion 15 projecting through an open side ofthe sleeve 11 and receivable in a transverse notch 16 in the front faceof the bit shank. A suitable clearance space 17 may be formed betweenthe elastomeric material and the curved The bit support has a transversebore 10 openouter surface of the detent portion to permit the detentelement to be forced with a turning action upwardly and inwardly by aninclined surface 18 on the inner front portion of the bit shank as thelatter is inserted in the support socket. As the projecting end portionof the detent element is turned upwardly and inwardly a turning ortwisting action is applied to the resilient plug relative to its outersleeve 11 and the torsional force so provided is transmitted through thedetent element to the bit shank thereby to apply an inward thrust to thebit shank to hold the head shoulder 7 against the outer surface of thebit support. Thus the detent element not only holds the bit in cuttingposition on its support but also imparts an inward thrust to the bitshank due to the torsional spring action of the elastomeric material ofthe plug. When the bit is pried out in a suitable manner from its socketthe detent may spring back out of the shank notch. If desired, when thebit shank is released from the detent means, as shown in FIG. 3, thedownward swinging movement of the detent portion of the detent elementmay be limited by the underlying edge of the outer sleeve.

The modification shown in FIGS. 6, 9, 10, 11 and 12 has a similar bitsupport and cutter bit but with a modified detent means. In thisinstance, the curved detent portion is guided for arcuate movement alongthe inner wall 11' of the metal sleeve 11, and the resilient plug 21 inwhich the cylindric body 22 of the detent element is embedded has aclearance space 23 to permit such inward movement of the detent portion.The elastomeric material of the plug is bonded at 24 to the inner wallof the detent portion 20 as Well as to the cylindric body portion 22. InFIGS. 7 and 8 a modified detentelement is shown with the curved detentportion 20' connected by spaced armlike portions 25 to the axiallyspaced end portions of a cylindric body 22'. The metal sleeve, in thisinstance, has a curved bent portion 26 in guiding engagement with thecurved inner wall 27 of the detent portion 29'. The bit shank istransversely notched at 28, as shown most clearly in FIGS. 6, 10 and 11,and has an inclined surface 29 at its front inner portion. When the bitshank is inserted in the support socket (FIG. 10) the inclined surface29 engages the detent portion 20 and forces the latter arcuatelyinwardly along the inner wall of the metal sleeve 11, pressing orsqueezing the elastomeric material, so that when the detent portion isopposite the notch 28 the built-up torsional spring action of theelastomeric material moves the detent into the notch. In FIG. 8 thedetent element is shown forcing the bit shank inwardly into the blocksocket yieldingly to urge the head shoulder 7 of the bit against theouter surface of the support. In FIG. 6 the elastomeric material urgesthe detent portion arcuately inwardly, and here, too, the detent portionmay be arranged to impart a thrust to the bit shank to urge the latterinward in the support socket. When the cutter bit is pried outwardly ina suitable manner the detent portion springs out of the shank notch.

There is shown in FIGS. 13 to 17 inclusive still another modification.As in the other forms of the invention a detent element 30 is embeddedin and bonded to the elastomeric material of a generally cylindricalblock in turn bonded to the inner wall of a cylindrical metal sleeve 31pressed or otherwise secured in position within a transverse bore in thecutter bit support. The detent element has a transverse body portion 32(FIG. 16) and a projecting detent portion 33, the latter beingengageable with .a notch in the bit shank as in the other embodimentsabove described. The metal outer sleeve has an inwardly bent portion at34 engaging the inner plane surface of the detent portion for guidingthe detent element for rectilinear movement along an oblique path ratherthan a torsional movement of the earlier forms above described.Evidently the detent element and the mounting may be so formed that thedetent portion may move slightly curvilinearly instead of rectilinearlywithout departing from the invention. When the bit shank is inserted inthe support socket 2, as shown in FIG. 15, the inclined surface 18' onthe bit shank engages the detent portion and shoves the detent portionupwardly and outwardly along a straight path, and when the notch 28'assumes a position opposite the detent element, the detent portion snapsinto the notch to hold the cutter bit in position on its support.Simultaneously the detent element imparts an inward thrust to the bitshank to urge the shoulder 7 on the outer bit head against the outersurface of the support. The cutter bit may be released from its supportsimply by prying outwardly with a suitable instrument to release thedetent element from the notch in the bit shank, as in the earlierembodiments.

In FIGS. 18 to 22 inclusive a still further modified embodiment isshown. In this instance, the cylindric metal sleeve has a resilient plugof elastorneric material such as rubber bonded in axial shear to itsinner wall, and ernbedded in and bonded to the resilient plug is adetent element 35 having a wedging surface 36 engageable, as shown inFIG. 19, with the bottom wall 37 of a recess or notch 38 in the frontface of the bit shank (see FIGS. 18 and 22). Evidently the side of thedetent element opposite the wedging surface may lie in the surface of acylinder, if desired. The detent element has an outer head portion 38 ofdisklike form providing an annular groove 39 for the reception of asuitable releasing instrument, indicated in dotted lines at 40 in FIG.20, whereby the detent element may be moved axially outwardly to releaseits wedge portion from the shank recess so that the bit shank may bewithdrawn from the support socket (FIG. 20). Thus the detent element notonly locks the bit shank in position but also imparts an inward thrustto the bit shank to hold the shoulder 7 on the outer bit head againstthe outer surface of the support. When the instrument 40 is releasedfrom the wedge groove the latter is moved axially inwardly by thespringlike action of the rubber-like material to bring the wedgingsurface 36 in wedging contact with the bit shank. The inclined surface13' on the inner forward portion of the bit shank forces the detentelement laterally upon insertion upon the bit shank into the supportsocket, and when the recess 38' assumes a position opposite the detentelement the latter snaps into the recess by the spring action of theelastomeric material of the rubber-like block in which the detentelement is embedded. Thus the detent may have both axial and lateralmovements as a result of the yielding of its resilient mounting.

The modification shown in FIGS. 23 to 27 inclusive comprises a detentelement 41 having a camlike detent portion or cam 42 and a cylindricbody portion 43, the latter being embedded in and bonded to the moldedelastomeric material of a cylindric plug or block 44 secured by bondingwithin an outer metal sleeve, as in the other embodiments. The ends ofthe detent body are desirably formed with polygonal sockets 45 for thereception of a suitable turning instrument indicated in dotted lines at46 in FIG. 24. The cam portion 42 of the detent element is engageable ina notch 46' in the front face of the bit shank and the detent not onlylocks the bit shank in position in its support but also, due to itscounterclockwise rotary cam action (FIG. 23) imparts an inward thrust tothe bit shank to hold the shoulder 7 on the outer bit head down againstthe outer surface of the supports. The detent element may be manuallyturned clockwise to the right, as viewed in FIG. 23, to move the camportion 42 out of the shank recess (FIG. 25) to enable insertion of thebit shank into or withdrawal of the same from the support socket. Alsothe inclined surface 47 on the inner forward portion of the bit shankmay force the detent element laterally as the bit shank is inserted intothe support socket and when the recess assumes a position opposite tothe detent position the latter may snap into the shank recess by thespring action of the elastomeric material in which the detent isembedded.

Evidently, in the several forms of the invention above described, thedetent has a dual duty, i.e. not only to hold the cutter bit in cuttingposition on its support but also to impart an inward thrust to the bitshank to urge the outer bit head against the outer surface of thesupport. Further, the support for the cutter bit may assume variousforms such as a lug for a cutter chain or a cutter arm of a rotaryboring head. Also instead of the elastomeric material for use as aspring other springlike means may be employed, as for example, ametallic torsion spring. Moreover the cylindric portion of the detentbody may have shapes other than cylindrical, as for example, a polygonalshape, so that the elastomeric material may be secured firmly thereto.

As a result of this invention an improved cutter bit and bit support areprovided having improved yieldable detent means for holding the cutterbit in cutting position on its support while permitting rapid release ofthe cutter bit from its support by a simple prying action. The improvedyieldable detent means not only acts to hold the cutter bit in cuttingposition on its support but also applies an inward thrust to the bitshank which must be overcome to effect release of the bit shank from thesupport socket. By the provision of the resilient torsional mounting forthe detent the latter is urged with a rotary motion toward lockingposition, in an improved manner. The improved resilient detent means isnot only relatively simple and compact in design but also may be appliedto a conventional cutter bit and bit support with a minimum of change.These and other advantages of the invention will be clearly apparent tothose skilled in the art.

While there are in this application specifically described several formsand modifications which the invention may assume in practice, it will beunderstood that these forms and modifications of the same are shown forpurposes of illustration and that the invention may be further modifiedand embodied in various other forms without departing from its spirit orthe scope of the appended claims.

What I claim as new and desired to secure by Letters Patent is:

1. In a cutting mechanism, the combination with a support having asocket and a cutter bit having a shank receivable in said socket, ofimproved means for holding the bit in cutting position on the supportcomprising a transverse bore in said support and entering the rear sideof said socket, a rotary lock arranged in said bore for rotationrelative to said support and having a locking element constantly urgedarcuately toward a complemental locking surface on the rear side of theinner portion of the bit shank, said locking element being maintainedagainst translatory movement relative to said locking surface of saidbit shank during movement of the latter into bit holding position, andresilient means for constantly urging said lock toward seated positionand against whose resilient yielding action the lock is releasable.

2. A cutting mechanism as set forth in claim 1 wherein said constantlyurging means includes resilient torsional means within said transversebore and said lock comprising a detent seated against the bit shank andconstantly urged arcuately inwardly toward bit holding position by saidtorsional means.

References Cited in the file of this patent UNITED STATES PATENTS

1. IN A CUTTING MECHANISM, THE COMBINATION WITH A SUPPORT HAVING ASOCKET AND A CUTTER BIT HAVING A SHANK RECEIVABLE IN SAID SOCKET, OFIMPROVED MEANS FOR HOLDING THE BIT IN CUTTING POSITION ON THE SUPPORTCOMPRISING A TRANSVERSE BORE IN SAID SUPPORT AND ENTERING THE REAR SIDEOF SAID SOCKET, A ROTARY LOCK ARRANGED IN SAID BORE FOR ROTATIONRELATIVE TO SAID SUPPORT AND HAVING A LOCKING ELEMENT CONSTANTLY URGEDARCUATELY TOWARD A COMPLEMENTAL LOCKING SURFACE ON THE REAR SIDE OF THEINNER PORTION OF THE BIT SHANK, SAID LOCKING ELEMENT BEING MAINTAINEDAGAINST TRANSLATORY MOVEMENT RELATIVE TO SAID LOCKING SURFACE OF SAIDBIT SHANK DURING MOVEMENT OF THE LATTER INTO BIT HOLDING POSITION, ANDRESILIENT MEANS FOR CONSTANTLY URGING SAID LOCK TOWARD SEATED POSITIONAND AGAINST WHOSE RESILIENT YIELDING ACTION THE LOCK IS RELEASABLE.